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A method for the axenic culture of marine microscopic algae that utilizes various types of paper as solid substrates for growth is described. Investigations into the growth of 39 algal, strains on various paper substrates were conducted. Applications of the method to bioassay are discussed.  相似文献   

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鸡菌属菌物是一类具有商业前景的食物蕈菌。对Termitomycesalbuminosus(Berk)Heim进行了广泛研究,其它种类的研究仅见于T.fulginosus(Berk.)Heim。笔者首次对T.robustus(Beeli)Heim粗柄鸡菌进行了纯培养研究,其菌丝体生长所需的碳源以麦芽糖为佳,葡萄糖、蔗糖次之;氮源以蛋白胨、酵母粉较好;天然材料的热水提取物,如松针、蚁巢圃、马铃薯、平菇出菇废料、蚕豆的混合物能促进菌丝生长;培养基在pH4.5左右最佳,可用0.05%的柠檬酸调节。菌丝体纯培养很容易形成大量分生孢子和小白球菌,表明小白球菌是粗柄鸡菌菌丝体无性繁殖过程的一个阶段。  相似文献   

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裂叶沙参和泡沙参种群有性生殖和无性繁殖的比较   总被引:13,自引:0,他引:13  
通过对裂叶沙参(Adenophora lobophylla Hong)和泡沙参(A.potaninii Korsh.)种群有性生殖和无性繁殖特性的对比,揭示濒危植物裂叶沙参的种群内部致濒机制。结果表明:裂叶沙参种群幼苗抢占草本层上层空间能力弱于泡沙参种群;裂叶沙参种群是以相对长的生殖期和高产籽量来适应环境;裂叶沙参种群开花结实量虽高于泡沙参种群,但其中成熟种子少,种子质量差,致使其种群由种子到一年生幼苗的转化率极低,并且幼苗生活力弱,是导致其种群濒危的重要内部原因。裂叶沙参种群除有性生殖外还兼有较弱的无性繁殖,是对其有性生殖的一个重要补充。  相似文献   

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Draparnaldia champlainensis sp. nov. is described and compared with other species of the genus and with Draparnaldiopsis. It closely resembles certain species described by Meyer from Lake Baikal and also Draparnaldiopsis simplex Jao. Its distinguishing features are (1) determinate branches borne in whorls on nearly every cell of the main axis; (2) one or a few broad hairs originating near the base of the determinate branch system; (3) a well-defined group of meristematic cells at the base of the hair; and (4) extensive rhizoidal cortication in the lower portions of the plants and at the base of the main branches. Draparnaldiopsis simplex Jao is transferred to the genus Draparnaldia and renamed Draparnaldia jaoi nom. nov.  相似文献   

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Algae- and bacteria-free seedling cultures of the seagrass Thalassia testudinwn Banks ex König were utilized to evaluate effects of nutrient enrichment on growth and chemical composition. Seedlings cultured in media based on both synthetic seawater and NH-15 medium amended with inorganic nitrogen (NH4+) and organic nitrogen (glutamine, glutamate, urea and yeast extract) exhibited no growth enhancement relative to controls in the growth parameters measured. General decreases in green leaf areas and leaf widths after one month coupled with relatively high C:N ratios after 3 months in culture suggest utilization and depletion of stored reserves with little or no assimilation of exogenous nutrients. These observations coupled with previous results in non-axenic seedling cultures indicate microbial associations may play a critical role in the nutrient physiology of this species.  相似文献   

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The life history of Spermatochnus paradoxus (Roth) Kütz. isolated from the Mediterranean Sea was studied in culture. Meiospores develop to a microscopic stage (microthallus) which at 20°C perpetuates asexually by plurilocular sporangia and formation of new microthalli. At 9°C microthalli act as homothallic gametophytes. Fusion of isogametes results in a diploid microthallus which, after differentiation of an apical cell, leads back to Spermatochnus plants. In addition, gametes develop without fusion to form haploid macrothalli, the further fate of which has not been determined. Chromosome numbers alternate between n = 20 ± 2 in the microthalli and 2n = 41 ± 4 in macrothalli.  相似文献   

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Caloglossa species are widely distributed in mangroves and salt marshes around the world and their life history patterns are being investigated in laboratory culture. In Australia all isolates of C. monosticha, C. postiae and C. ogasawaraensis have Polysiphonia‐type (P‐type) sexual life histories. Among the 70 C. leprieurii isolates from Australia and New Zealand P‐type sexual reproduction also is dominant. However, ten isolates of C. leprieurii from the Spencer Gulf and the Gulf of St. Vincent in South Australia give rise to successive tetrasporphyte generations without gametophytes. Moreover, one isolate from Queensland is asexual. Only one South Australia isolate, obtained from Lake Alexandrina at the mouth of the Murray River, is sexual. South Australia and Pacific Mexico are two regions in which asexual reproduction is dominant. In another mangrove dwelling red alga Bostrychia moritiziana (Rhodomelaceae) non‐sexual reproduction also is frequent in Australia, New Caledonia and Bali (Indonesia). This asexual reproductive pattern of tetrasporophytic recycling appears to have arisen independently among individual populations of various red algal species in different regions. Investigations are underway on the molecular phylogeny of the Caloglossa leprieurii isolates.  相似文献   

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新型生物杀虫剂--刺糖菌素   总被引:8,自引:0,他引:8  
刺糖菌素是由土壤放线菌多刺糖多孢菌(Saccharopolyspora spinosa)产生的次级代谢产物,是一种具有触杀及摄食毒性的广谱杀虫剂。对鳞翅目害虫而言,刺糖菌素是目前已发现的杀虫剂中选择性最高的化合物之一。中就刺糖菌素的结构、生物合成、性质以及生产方法进行了综述。  相似文献   

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The morphology, gross cytology, reproduction, and habitat ecology are described for Derbesia marina based on observations of New England field populations and laboratory cultures of this plant. These data, and additional observations on cultures of several other species of Derbesia from elsewhere and on type and other important collections, have been used to evaluate the systematic relationship of New England Derbesia with other species of this genus. The single Derbesia species in New England is referred to D. marina. The systematic criteria previously used to distinguish species within Derbesia are reviewed and interpreted within the context of the present investigation. In systematic studies, we stress the importance of the use of sporangial and chloroplast morphology, the presence or absence of pyrenoids, and reproductive history. Two types of life history are reported for D. marina in New England: (1) A form of D. marina collected at 20 m reproduces directly with stephanokontous zoospores growing into sporophytic plants of Derbesia morphologically identical to their parent thalli. (2) On the other hand, at least some New England, populations of D. marina have retained the genetic potential for producing a sexual generation (Halicystis ovalis), even though the latter is unknown for the coast of northeastern North America.3 Gametophytes (H. ovalis) were produced directly from enlargement and subsequent differentiation of uncleaved lateral sporangia in 2 cultured populations of New England D. marina. A single female and numerous male vesicles formed in this manner produced gametes, but neither fertilization nor parthenogenesis occurred; thus the entire life history was not completed in culture. The occurrence of the directly reproducing deep water form of D. marina is presented as evidence for speciation of a sporophyte (Derbesia) independent of its alternate gametophyte (Halicystis). An hypothesis is advanced to explain the source and means for expression of genetic variability necessary for speciation in a population of nonsexually reproducing Derbesia.  相似文献   

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